The foundational industrial process known as Chlor-Alkali involves the electrolysis of aqueous sodium chloride (brine) to simultaneously yield chlorine gas, sodium hydroxide (caustic soda) and hydrogen gas — a set of chemicals that serve as critical feedstocks in a wide range of downstream sectors. These products from the chlor-alkali sector underpin many everyday applications such as water treatment (via chlorine or sodium hypochlorite), pulp and paper manufacturing, textiles, alumina refining, soaps and detergents, and the production of vinyl derivatives. The efficiency of the process is heavily influenced by the type of electrolytic cell used — for example, diaphragm cells, mercury cells and the increasingly preferred membrane cell systems. As the industry transitions to greener technologies, membrane cells are taking centre stage due to their lower energy consumption, reduced environmental emissions and elimination of mercury hazards. The interdependence of chlorine and caustic soda production means that supply and demand must remain balanced — since the electrolysis process necessarily generates these chemicals in set proportions, market adjustments often hinge on downstream usage of one to match output of the other. Advances in the chlor-alkali field are therefore shaped by developments in infrastructure, regulatory pressure on emissions, energy cost dynamics and growth of end-use industries like PVC, aluminium, and water-treatment chemistry. As urbanisation accelerates and heavy industrial sectors expand globally, the role of chlor-alkali derived chemicals remains indispensable in supporting manufacturing ecosystems, ensuring material flows, underpinning modern hygiene and sanitation systems, and enabling chemical synthesis on a massive scale in the era of industrialisation.